A typo and an attempt at a quality of life change #430

 # set cleaned up colnames to current output colnames
    cnames <- c(contractsymbol = "ContractID",
                contractsize = "ConractSize",
                currency = "Currency",

getOptionChain.yahoo <- function(Symbols, Exp, ..., session=NULL)
{

  omit <- list(...)$omit   # defined the omit argument here
  
  NewToOld <- function(x, tz = NULL, omit = NULL) {
    if(is.null(x) || length(x) < 1)
      return(NULL)
      
      
# ...

    # convert trade time to exchange timezone
    d$LastTradeTime <- .POSIXct(d$LastTradeTime, tz=tz)
    
    # Omit specified columns if 'omit' is provided
    if(!is.null(omit)) {
      d <- d[ , !(names(d) %in% omit), drop=FALSE]
    }
    
    return(d)
  }
  
  if (is.null(session)) {
    session <- .yahooSession()
  }
  if (!session$can.crumb) {
    stop("Unable to obtain yahoo crumb. If this is being called from a GDPR country, Yahoo requires GDPR consent, which cannot be scripted")
  }
  
# ...

 if(is.null(Exp)) {
      # Return all expiries if Exp = NULL
      out <- lapply(all.expiries, function(e) {
        getOptionChain.yahoo(Symbols, e, .expiry.known=TRUE, session=session, omit=omit) # added omit here
      })
      # Expiry format was "%b %Y", but that's not unique with weeklies. Change
      # format to "%b.%d.%Y" ("%Y-%m-%d wouldn't be good, since names should
      # start with a letter or dot--naming things is hard).
      return(setNames(out, format(all.expiries.posix, "%b.%d.%Y")))
    } else {
      # Ensure data exist for user-provided expiry date(s)
      if(inherits(Exp, "Date"))
        valid.expiries <- as.Date(all.expiries.posix) %in% Exp
      else if(inherits(Exp, "POSIXt"))
        valid.expiries <- all.expiries.posix %in% Exp
      else if(is.character(Exp)) {
        expiry.range <- range(unlist(lapply(Exp, .parseISO8601, tz="UTC")))
        valid.expiries <- all.expiries.posix >= expiry.range[1] &
          all.expiries.posix <= expiry.range[2]
      }
      if(all(!valid.expiries))
        stop("Provided expiry date(s) not found. Available dates are: ",
             paste(as.Date(all.expiries.posix), collapse=", "))
      
      expiry.subset <- all.expiries[valid.expiries]
      if(length(expiry.subset) == 1)
        return(getOptionChain.yahoo(Symbols, expiry.subset, .expiry.known=TRUE, session=session, omit=omit)) # added omit
      else {
        out <- lapply(expiry.subset, function(e) {
          getOptionChain.yahoo(Symbols, e, .expiry.known=TRUE, session=session, omit=omit) # added omit 
        })
        # See comment above regarding the output names
        return(setNames(out, format(all.expiries.posix[valid.expiries], "%b.%d.%Y")))
      }
    }
  }